1. Allen, M. 1933. Letter from to C.R. Fay. Marshall Library Archives, Reference: Pigou 2/3. Cambridge.
2. Bowley, A.L. 1933. Letter to A.C. Pigou. Marshall Library Archives, Reference: Pigou 2/3. Cambridge.
3. Kahn, R.F. 1933. Note from to A.C. Pigou. Marshall Library Archives, Reference: Pigou 2/3. Cambridge.
4. Pigou, A.C. 1933a. Theory of Unemployment. Editions card, London: Macmillan Publishers Ltd Archive Record.
5. ———. n.d. Letter from A.C to Richard Stone. Stone, J.N.R. Papers, King’s College Archive Centre, Reference: JNRS/3/1/102.